JPH02153251A - Slide throttle valve type carburetor - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a carburetor that supplies and controls a mixture to an engine.
In particular, the present invention relates to a sliding throttle valve type carburetor in which a throttle valve is movably disposed within a throttle valve guide cylinder connected to an intake passage passing through the carburetor body.

[Conventional technology]

Conventionally, a structure in which a sliding throttle valve of a carburetor is slidably disposed in a throttle valve guide cylinder via a bearing is disclosed in Japanese Patent Application No. 61-125016 filed by the present applicant. This is a sliding throttle valve with a bearing rotatably supported at the end.
This bearing slides and guides the throttle valve guide cylindrical surface, thereby operating the sliding throttle valve.

[Problem to be solved by the invention]

According to such a conventional sliding throttle valve type carburetor, a bearing made of bearing steel contacts the throttle valve guide cylinder surface of the carburetor body made of aluminum alloy or zinc alloy, and the hardness is lower than that of bearing steel. This is undesirable because the soft carburetor body may wear out. For this purpose, a rail member such as stainless steel was attached to the sliding portion of the bearing of the throttle valve guide cylinder of the carburetor body.

According to this, although the problem of wear has been resolved,
It is necessary to prepare a plurality of relatively long rail members ranging from low to high opening degrees of the sliding throttle valve, and the number of man-hours required for attachment to the carburetor body increases, leading to an increase in the cost of the product.

[Means to solve problems]

The purpose of the sliding throttle valve type carburetor of the present invention is to provide a carburetor that is low in product cost and has less wear between the sliding throttle valve and the throttle valve guide tube, and achieves the above objectives. For this purpose, a throttle valve guide tube 3 is provided in a slide throttle valve of a carburetor in which a throttle valve guide tube is provided adjacent to the intake passage passing through the carburetor body, and a sliding throttle valve is disposed within the throttle valve guide tube. The engine-side guide surface 3A to be formed and the air cleaner-side guide surface 3B opposing thereto are formed as parallel surfaces having a constant gap H, while end surfaces on both sides of the sliding throttle valve 4 across the intake passage 2 are formed. 4A and 4B are bearings 5 guided by the engine side guide surface 3A and the air cleaner side guide surface 3B.
is rotatably arranged, and a ring member 7 made of a synthetic resin material is fitted to the outer peripheral rotating portion 5A of the bearing 5, and the sliding throttle valve 4 is connected to the throttle valve guide cylinder 3 through the ring member 7. It is slidably guided by an engine side guide surface 3A and an air cleaner side guide surface 3B.

[Effect]

A ring member made of a synthetic resin material placed around the outer periphery of a bearing rotatably supported by the sliding throttle valve rolls into contact with the throttle valve guide cylinder of the carburetor body, and the ring member is made of a synthetic resin material. As a result, the frictional resistance during sliding of the sliding throttle valve can be halved, and the wear of the sliding contact portion can be reduced.

〔Example〕

Hereinafter, one embodiment of the sliding throttle valve type carburetor according to the present invention will be described with reference to FIGS. 1 and 2.

Reference numeral 1 denotes a carburetor body through which an intake passage 2 passes horizontally, and a throttle valve guide cylinder 3 opens upward from the middle of the intake passage 2 and is connected thereto. This carburetor body 1 is made of aluminum alloy or zinc alloy. The cross-sectional shape of the throttle valve guide tube 3 is rectangular, and at least the engine side guide surface 3A (the right side surface of the throttle valve guide tube 3) and the air cleaner side guide surface 3B (the left side surface of the throttle valve guide tube 3). ) are planar, and the gap H between them is constant and parallel.

Reference numeral 4 designates a sliding throttle valve that is slidably disposed within the throttle valve guide cylinder 3 and opens and closes the intake passage 2, and the two ends 4A and 4B that sandwich the intake passage 2 are provided with vertically extending holes (see FIG. 1). ), a plurality of bearings 5 are mounted on both end surfaces 4A of the sliding throttle valve 4.
, 4B are rotatably supported on shafts 6 respectively erected. Furthermore, a ring member 7 made of a synthetic resin material is fitted into the outer peripheral rotating portion 5A of the bearing 5. The ring member 7 therefore rotates synchronously with the bearing 5.

When the sliding throttle valve 5 with the bearing 5 mounted thereon is inserted into the throttle valve guide cylinder 3, the outer circumferential surface of the ring member 7 of the bearing 5 touches the throttle valve guide cylinder when the sliding throttle valve 4 is moved. It rotates while contacting the engine side guide surface 3A and the air cleaner side guide surface 3B of No. 3.

Note that 8 is an operation wire that applies an opening operation force to the sliding throttle valve 4. Further, the thickness L of the intake passage '2 of the sliding throttle valve 4 in the longitudinal axis direction is smaller than the constant gap H between the parallel surfaces of the engine side guide surface 3A and the air cleaner side guide surface 3B.
Further, the outer diameter of the ring member 7 of the bearing 5 is smaller than the gap H of the throttle valve guide tube 3 and larger than the thickness L of the slit sliding throttle valve 4.

When the sliding throttle valve 4 moves vertically in FIG. 1, the ring member 7 of the bearing 5 rotates and connects the engine side guide surface 3A and the air cleaner side guide surface 3BJ- It is something that moves.

In particular, by arranging the ring member 7 made of a synthetic resin material on the outer peripheral rotating portion 5A of the bearing 5,
Compared to the friction coefficient of conventional bearing steel, which is 0.25 to 0.3, the friction coefficient has been halved to 0.12 to 0.15, and the sliding properties have been significantly improved. Even if the throttle valve guide tube 3 of the carburetor main body 1 made of alloy or zinc alloy is used as it is, there will be no wear on the sliding surfaces of each other.

Note that the engine-side guide surface 3A and the air cleaner-side guide surface 3B, which are parallel surfaces with a constant gap H, need only correspond to the ring member 7 of the bearing 5 attached to the sliding throttle valve 4. The cross-sectional shapes of the throttle valve guide tube 3 and the sliding throttle valve 4 are not limited to rectangular shapes.

Further, the bearing itself may be made of synthetic resin material. Furthermore, it can be fully used as a guide for the negative pressure valve of a constant vacuum type vaporizer, and the dynamic characteristics of the negative pressure valve can be improved.

〔Effect of the invention〕

As described above, the sliding throttle valve type carburetor according to the present invention has the following effects.

By arranging a ring member made of a synthetic resin material around the outer circumference of the bearing and allowing the sliding throttle valve to slide into the throttle valve guide cylinder, the sliding resistance between the bearing and the throttle valve guide cylinder is increased. Because of this, the throttle valve guide tube made of aluminum alloy or zinc alloy can be used as is, and expensive rails such as stainless steel are no longer required, so parts costs and assembly costs can be reduced. be.

In addition, there is a slight gap between the ring member, the engine side guide surface, and the engine and yake cleaner side guide surfaces. Pulsating pressure is generated within 2. When large pulsating pressure acts on the sliding throttle valve, the sliding throttle valve reciprocates in the direction of the longitudinal axis of the intake passage, and the bearing and each guide surface may collide. The ring member absorbs the collision sound, thereby reducing vibration and hammering noise.

In addition, it is expected that the ring member will wear out slightly when used for an extremely long period of time, but in this case, it will be possible to reuse it by simply replacing the ring member, and the parts cost and replacement work for replacement will be It is extremely cheap and easy.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of the main parts of the bearing part of the sliding throttle valve type carburetor according to the present invention (1-1 in FIG. 2) when viewed from the side.
2 is a cross-sectional view taken along the line TI-11 in FIG. 1. i , Carburetor body 2 , Intake path 3
, , , Throttle valve guide tube 3A, , Engine side guide surface 3B, , , Air cleaner side guide surface 4...
・・Sliding throttle valve 5 ・・・・Bearing 7 ・
,,,ring member

Claims (3)

[Claims] (1) In a sliding throttle valve of a carburetor in which a throttle valve guide tube is provided in series with the intake passage passing through the carburetor body and a sliding throttle valve is disposed within the throttle valve guide tube, the throttle valve guide tube 3 The engine side guide surface 3A that forms the air cleaner side guide surface 3B that opposes the engine side guide surface 3A and the air cleaner side guide surface 3B that opposes it are formed as parallel surfaces having a constant gap H, while A bearing 5 guided by the engine-side guide surface 3A and the air cleaner-side guide surface 3B is rotatably disposed on the end surfaces 4A, 4B, and a ring member 7 made of a synthetic resin material is provided on the outer peripheral rotating portion 5A of the bearing 5. The sliding throttle valve 4 is connected to the engine side guide surface 3A of the throttle valve guide tube 3 and the air cleaner side guide surface 3 through the ring member 7.
A sliding throttle valve type carburetor that is slidingly guided by B. (2) A constant gap H between the parallel surfaces of the engine-side guide surface 3A and the air cleaner-side guide surface 3B of the throttle valve guide cylinder is determined by the thickness L in the longitudinal axis direction of the intake passage 2 of the sliding throttle valve 4. A sliding throttle valve type carburetor according to claim 1, wherein the sliding throttle valve type carburetor is larger. (3) The outer diameter K of the bearing 5 into which the ring member 7 is fitted is smaller than the gap H between the engine side guide surface 3A and the air cleaner side guide surface 3B of the throttle valve guide cylinder 3, and the sliding throttle valve 4. The sliding throttle valve type carburetor according to claim 1, wherein the thickness L in the longitudinal axis direction of the intake passage 2 is greater than the thickness L in the longitudinal axis direction of the intake passage 2 of the fourth embodiment.